Business Description, Organization and Basis of Presentation (Details) - shares	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Ownership structure of AB Holding
Units outstanding (in units)	100,000	100,000
AB Holding \| EQH
Ownership structure of AB Holding
General partnership interest (percent)	4.00%
AB Holding \| AllianceBernstein Corporation
Ownership structure of AB Holding
General partnership interest (percent)	1.00%
Units outstanding (in units)	100,000
Limited partners or members ownership interest in Company (percent)	36.50%
EQH and its subsidiaries \| AllianceBernstein Corporation
Ownership structure of AB Holding
Limited partners or members ownership interest in Company (percent)	62.80%
Unaffiliated holders \| AllianceBernstein Corporation
Ownership structure of AB Holding
Limited partners or members ownership interest in Company (percent)	0.70%
AB \| AllianceBernstein Corporation
Ownership structure of AB Holding
Limited partners or members ownership interest in Company (percent)	100.00%
AB \| EQH and its subsidiaries
Ownership structure of AB Holding
General partnership interest (percent)	64.30%

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The number of general partner units outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 5
-Subparagraph (SAB Topic 4.F)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187171-122770

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Percentage investment held by the managing member or general partner of the limited liability company (LLC) or limited partnership (LP).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

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Percentage investment held by members or limited partners of limited liability company (LLC) or limited partnership (LP).

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